Proacta Incorporated and Yakult Honsha Announce an Agreement for the Collaborative Research, Development and Commercialization for Proacta's PR509 Compound

SAN DIEGO, Feb. 22, 2011 /PRNewswire/ -- Proacta Incorporated and Yakult Honsha Co., Ltd. (Tokyo: 2267) today announced the execution of a definitive agreement relating to the collaborative research, development and commercialization of Proacta's PR509, a hypoxia-activated pro-drug for the treatment of cancer.

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"We have worked diligently to arrive at this significant agreement with Yakult and we are very pleased to announce its execution," said John C. Gutheil, MD, Proacta's CEO. "This achievement underscores the commitment that our two companies have to a long-term, mutually rewarding relationship. It also exemplifies the ability of Proacta to leverage relationships with pharmaceutical partners to foster the likelihood of market success for its proprietary line of hypoxia-activated pro-drugs. We view this partnership with Yakult as further validation of the hypoxia-activated pro-drug platform and its potential as a novel therapeutic agent for patients suffering from cancer."

Mr. Shigeyoshi Sakamoto, Head, Pharmaceutical Division/ Managing Director, Member of the Board of Yakult, said, "We are delighted to have reached an agreement with Proacta regarding their PR509 for the research, development, and commercialization in Japan. The unique mechanism of action and well-developed preclinical data provide Yakult with the confidence necessary to join with Proacta in completing the preclinical and early clinical studies in the US in a collaborative manner. This collaboration should allow us to more quickly bring promising new treatments to patients suffering from cancer. We look forward to our work with Proacta through the collaborative research and development of PR509."

About PR509

PR509 is Proacta's proprietary hypoxia-activated irreversible multi-kinase inhibitor discovered at the Auckland Cancer Society Research Centre, University of Auckland, New Zealand.  Reversible multi-kinase inhibitors (MKI) are currently in use for the treatment of several types of cancer.  However, resistance often develops to reversible MKI's.  In addition, reversible MKI's have side effects that limit the use of higher doses.  PR509 utilizes an irreversible MKI that is activated only in areas of severe hypoxia, a characteristic of most solid tumors.  Localized release of the irreversible MKI leads to higher concentrations in the tumor relative to normal tissues, which should result in improved efficacy and fewer side effects.  In addition, irreversible MKI inhibitors are not subject to some of the resistance mechanisms applicable to reversible MKI inhibitors.

Clinical Development Status

PR509 is currently targeted for development in non-small cell lung cancer resistant to reversible tyrosine kinase inhibitors such as erlotinib and /or gefitinib, where an effective treatment has yet to be established.  In addition to NSCLC, Proacta expects to evaluate PR509 in other cancers such as gastric, breast, and pancreatic that are currently treated with first-generation reversible tyrosine kinase inhibitors.

About Proacta Incorporated

Proacta is a San Diego based biotechnology company dedicated to the development and commercialization of hypoxia-activated oncology drugs. Proacta is currently conducting a phase II study of PR104, a hypoxia activated alkylator, in patients with relapsed or refractory leukemia.  In addition, Proacta has a pipeline of hypoxia-activated prodrugs for the treatment of cancer that are licensed from the University of Auckland in New Zealand.  For more information on Proacta, visit the Proacta web site at www.proacta.com.

About Yakult

Yakult is a leading Japanese company focused on the development and marketing of pharmaceuticals, foods, beverages, and cosmetics. With respect to its pharmaceutical business, Yakult has an emerging presence in oncology. For more information on Yakult, visit: http://www.yakult.co.jp/english/index.html or view the following company profile:

http://www.yakult.co.jp/english/pdf/profile2010-2011.pdf

SOURCE Proacta Incorporated